Working with male rodents may increase risk of all_ergy to laboratory animals

Abstract
Background: Our aim was to study the risk of laboratory animal all_ergy (LAA) among research staff working in laboratories separate from the animal confinement area. The roles of atopy and exposure intensity in LAA were studied with special regard to exposure to male rodents, who excrete higher levels of urinary all_ergens than female rodents. Methods: Eighty rodent‐exposed subjects gave blood samples for the analysis of total IgE, Phadiatop, and specific IgE against rat (RUA) and mouse urinary all_ergens (MUA), and answered questionnaires. Air samples were collected for RUA and MUA aeroall_ergen measurement in both laboratories and animal confinement facilities. Results: Twenty percent of the subjects had IgE >0.35 kU/l to RUA and/or MUA, and 32% had experienced animal work‐related symptoms, although 90% of aeroall_ergen samples from the research department laboratories were below the detection limit (3 and 100 kU/l, other all_ergies (especiall_y to other animals), or more than 4 years of exposure significantly increased laboratory animal sensitization and symptoms. Working with mainly male rodents gave odds ratios (95% CI) of 3.8 (0.97–15) for sensitization and 4.4 (1.4–14) for symptoms. Subjects with both exposure to mainly male rodents and atopy or elevated total IgE had a 10‐fold higher frequency of sensitization than exposed subjects with neither risk factor. Conclusions: A majority of subjects with a combination of exposure to mainly male rodents and atopy or elevated total IgE developed sensitization to and symptoms from laboratory animals. Current low exposure seems to maintain the presence of specific IgE. Further measures must be undertaken to provide a safe workplace for laboratory animal workers.